Defensive TOTY champions erased from set when set updated with TOTY release 2

I had purchased all of the release 1 TOTY players and placed them into sets the weekend release 1 came out with the exception of Mailata and Wagner who I put into my lineup. 
When release 2 of TOTY was released, the sets updated. The offensive players I had already placed in there were still there, but the 6 defensive champions that were placed in there from release 1 disappeared from my account. I've heard of at least 2 other people who experienced the same thing, again only with the defensive TOTY champions set.